If you’re a peanut butter lover, this Peanut Butter Sheet Cake with Peanut Butter Frosting is about to become your new go-to dessert. It’s soft, rich, and perfectly moist, with a dense yet tender crumb that melts in your mouth. Topped with a creamy, sweet peanut butter frosting that’s whipped until smooth, every bite delivers pure comfort and indulgence. Whether you’re baking for a potluck, a birthday party, or a casual weeknight treat, this cake brings home-style flavor with minimal fuss. It’s the kind of recipe that feels nostalgic—like something your grandmother might’ve made—but still fits perfectly into any modern-day celebration.
The beauty of this recipe is how effortlessly it comes together. It’s all made in a sheet pan, which means no stacking, layering, or fancy decorating skills are required. Just bake, frost, slice, and serve. It’s great for feeding a crowd, storing leftovers, or making ahead of time. The cake itself is infused with peanut butter flavor that’s not too sweet or overpowering, and the frosting is the ideal finish: silky, rich, and full of nutty goodness. Together, they create a balanced dessert that’s satisfying without being too heavy.
This cake is also endlessly customizable. Whether you want to sprinkle chopped peanuts on top, swirl in a touch of chocolate, or add a layer of jelly between the cake and frosting, you can tailor it to your taste. It’s a classic dessert that’s easy to love and even easier to make, which is exactly why it should be part of your recipe rotation.
Storage Options
Store covered at room temperature for up to 3 days or in the refrigerator for up to 5 days. You can freeze unfrosted or fully frosted cake for up to 2 months—thaw in the fridge before serving.
Summary
A moist peanut butter sheet cake topped with creamy peanut butter frosting. Perfectly rich, easy to make, and ideal for serving a crowd.
Why You’ll Love This Recipe
Bold peanut butter flavor, easy one-pan baking, crowd-pleasing texture, and a silky frosting that pulls it all together.
Kitchen Equipment You’ll Need
Sheet pan (10×15 inches)
Large mixing bowls
Hand or stand mixer
Whisk and spatula
Saucepan
Measuring cups and spoons
Tips for Success
Use creamy peanut butter for the smoothest texture
Don’t overmix the batter—just until combined
Let the cake cool before frosting to prevent melting
Frost while the cake is slightly warm for a glaze-like finish
Ingredients
For the Cake:
1 cup water
1 cup unsalted butter
1 cup creamy peanut butter
2 cups granulated sugar
½ cup sour cream
2 eggs
1 tsp vanilla extract
2 cups all-purpose flour
1 tsp baking soda
½ tsp salt
For the Frosting:
½ cup unsalted butter
¼ cup creamy peanut butter
¼ cup milk
2½ cups powdered sugar
½ tsp vanilla extract
Directions
Preheat the oven to 350°F and grease a 10×15-inch sheet pan.
In a saucepan, bring water, butter, and peanut butter to a boil, then remove from heat.
In a large bowl, whisk together sugar, sour cream, eggs, and vanilla. Slowly add the peanut butter mixture and stir until combined.
Add flour, baking soda, and salt. Stir until just mixed.
Pour batter into prepared pan and bake for 20–25 minutes or until a toothpick inserted in the center comes out clean.
While the cake cools slightly, make the frosting. In a saucepan, melt butter, peanut butter, and milk. Bring to a gentle boil, then remove from heat and whisk in powdered sugar and vanilla until smooth.
Pour frosting over the warm cake and spread evenly. Let cool completely before slicing.
Additional Tips or Variations
Top with chopped peanuts or mini chocolate chips for texture
Add a swirl of jelly on top for a PB&J twist
Use natural peanut butter for a less sweet, more intense flavor
Swap sour cream with plain yogurt if preferred
